At present, several typologies of cooking tops are available on the market, the most widespread typology using one or more gas burners, wherein the amount of heat necessary for cooking food is generated through combustion of a gas appropriately mixed with air.
Systems of burners are also known in the art, which have a substantially circular shape and have two concentric burners, typically an outer burner and an inner burner.
Such systems of burners are known as “double-crown”, and include gas supply means, said supply means comprising, for example, a pair of gas inlet ducts associated with independent control valves, so that the two burners (i.e. the outer burner and the inner burner) can be used either together or separately in order to achieve good variability and a homogeneous distribution of the heat to be supplied to the cooking containers. As an alternative, both concentric burners may be fed by a single gas inlet duct, with an associated tap, which simultaneously feeds the different intake channels that supply the air-gas mixture to the concentric burners.
Such systems of burners further include a cup comprising at least one first chamber for supplying the air-gas mixture to the inner burner and at least one second chamber for supplying said air-gas mixture to the outer burner, said cup being associated with the supply means and with at least one flame divider (or cap).
The cup and the flame divider may be positioned on the cooking top where the system of burners is installed, and use the air above the cooking top as primary air to be mixed with the gas.
Also, the cup is usually made of die-cast aluminum, while the flame divider or cap is usually made of enameled cast iron (or brass alloy or steel) and acts as a cup closing element.
These systems of burners known in the art typically propagate a flame known as “crown flame”; a “crown flame” is a flame with a substantially radial direction of propagation, i.e., a flame that propagates outwards from the gas burner in a substantially radial direction with respect to the burner axis, and therefore in a direction which is substantially tangential to a visible surface of the cooking top. Said “crown flame”, when emitted at an insufficient height above the cooking top, may cause low-CO2 combustion, resulting in the generation of a high level of unburnt products (CO and NOx).
Systems of burners are also known in the art which have a flame divider or cap with a plurality of apertures adapted to generate a “carpet flame”, i.e., a flame that propagates out of the system of burners in a substantially axial direction with respect to the axis of the system of burners, and therefore in a direction which is substantially orthogonal to a visible surface of the cooking top.
A carpet flame may be a total carpet flame or a perimetric carpet flame, depending on whether it covers a geometric figure (generally a circle) entirely or just the peripheral portion of said geometric figure (generally a circular crown).
Also in the case of a perimetric carpet flame, a plurality of concentric rows of apertures can generate a “carpet flame”, in particular for the purpose of optimally heating also the central portion of the base of a cooking vessel positioned over the gas burner.
However, the solutions known in the art suffer from a few drawbacks.
In particular, in the solutions known in the art, the components of the system of burners are substantially made by die casting, being typically made of die-cast aluminum alloys; it is clear that this solution is an expensive one, and therefore a cooking top comprising such a system of burners will implement solutions that are not very effective in economical terms.
Furthermore, in the solutions known in the art, the flame divider is positioned flush with the visible surface of the cooking top. When the system of burners is in use, it has been noticed that such a realization may cause overheating of that area of the visible surface of the cooking top which is closest to the system of burners; it is clear that this overheating may also cause damages to the cooking top, particularly when the latter is made from glassy materials or the like.